The artist formerly known as EDH, Commander delivers five outstanding slices of fun in the form of complete 100 card decks, each with only one copy of each card, making for a ton of variety in gameplay. all five provide a fabulous multiplayer experience. Because Commander is specifically aimed at the multiplayer market, Wizards of the Coast have been able to give free reign to greenlight cards which wouldn't necessarily make it in to regular Magic expansions. Death by Dragons, for example, gives every player a 5/5 red flying Dragon. Every player, that is, except one. Who's winning? Who's been attacking you? Who keeps countering the wrong spells? Yeah, that one. With foolish amounts of entertaining card interactions, this is the perfect excuse to get four friends round the gaming table, and see who really is the master and Commander.
An excellent way to play. These are great on their own or as a base. The more friends you have the more fun (and time).
Before returning to MtG recently, I had been away from the game for over 10 years. This means I missed A TON of cards. When I came back, this appeared to be an extremely popular format, and these decks seem like a good way to introduce yourself to the format. Trying to build a deck on your own after you've missed so much time can be very overwhelming.